A film insert molded article in which a film printing a pictograph, a mark, a design or the like thereon is molded integrally with an injection-molded article is formerly known as one of decorating techniques of the injection-molded article.
For example, the film insert molded article is manufactured as follows (see Japanese Patent Laid-Open No. 63-34814). Namely, a decorating film having a display section of a keyboard printed on a face of the front side of a synthetic resin film able to be thermoformed is thermoformed in a shape of a surface of a keyboard panel so that a film for coating is made. The film for coating is then arranged within a die, and molten resin is injected from a rear side of the film for coating into the die so that the film insert molded article is manufactured.
In the above former manufacturing method of the film insert molded article, the film is thermally shrunk when the film arranged within the die is thermoformed. A heat shrinking amount due to the thermoforming is increased as a product size is increased. Therefore, in the former manufacturing method of the film insert molded article, the size of the film arranged within the die is determined by predicting the heat shrinking amount in advance.
However, when the product size of the film insert molded article is increased, variation in the heat shrinking amount is also increased. Accordingly, there are disadvantages in that the actual heat shrinking amount becomes larger than the predicted heat shrinking amount, and no entire surface of the keyboard panel can be coated with the film for coating, and a resin layer is seen in the7 front in some cases.
Further, when the actual heat shrinking amount is reversely smaller than the predicted heat shrinking amount, there are disadvantages in that an excessive portion is generated in the film for coating arranged within the die, and a wrinkle is generated in the film when the surface of the film insert molded article is coated.